In a comment to this post, reader Westmorlandia offered the following:
I usually prefer “on behalf of” when talking about execution, as otherwise some lawyer will try to argue that a contract signed through agency (almost always the case with companies) was not signed “by” the company.
So, the question is, would there be any benefit to saying “signed on behalf of Acme” rather than “signed by Acme”? Would your answer depend on whether the person signing for Acme was (1) the CEO, (2) the CEO of a member, or (3) someone with a power of attorney?
Life would be simpler is you could use by regardless of whether the party is an individual or an entity. So the question is whether anyone has ever halfway plausibly argued that a given contract didn’t comply with some requirement or other because it was signed by an agent of Acme and the requirement referred to signature “by” Acme?